The technology of the present disclosure relates to an image forming apparatus that forms a color image by using a plurality of image carrying members.
In the related art, there has been known an image forming apparatus that forms a color image by using a plurality of image carrying members. In this type of image forming apparatus, toner images formed on the plurality of image carrying members are transferred onto an intermediate transfer belt and the toner images transferred onto the intermediate transfer belt are transferred onto a transfer material, so that the color image is formed.
In this type of image forming apparatus, it is necessary to form the toner images on the intermediate transfer belt with a constant concentration. Therefore, an ID sensor is used in order to detect the concentration of the toner images on the intermediate transfer belt. The ID sensor emits inspection light toward the intermediate transfer belt, and detects the concentration of the toner images on the intermediate transfer belt on the basis of a light receiving amount of the inspection light reflected by the intermediate transfer belt.
In this type of image forming apparatus, an ID sensor 80 is provided to a board 81 as illustrated in FIG. 11. As illustrated in FIG. 12, in the ID sensor 80, a sensor body 82 having a light emitting unit 91 and a light receiving unit 92 is integrally formed with the board 81. A lens 83 is held to a holding member 84, which is mounted to the board 81, to control emitted light from the sensor body 82 and incident light to the sensor body 82. In FIG. 11, a lid member 85 forming a box body provided therein with the holding member 84 and the sensor body 82 is mounted to the board 81 from an opposite side of the holding member 84.
When the holding member 84 and the lid member 85 are mounted to the board 81, for example, two pins (bosses) 86 of the holding member 84 are allowed to be inserted into through holes 81a of the board 81 as illustrated in FIG. 13, and the two pins 86 are allowed to be inserted into through holes 85a of the lid member 85 as illustrated in FIG. 14. In this state, a distal end portion of each pin 86 is melted and is welded to the lid member 85. In this way, the holding member 84 is directly welded and fixed to the lid member 85. By this welding and fixing, the ID sensor 80 is mounted to the board 81.